Artificial daylight fixture



Oct. 13, 1964 MLQGANGBIN ARTIFICIAL DAYLIGHT FIXTURE Filed June 9, 1960 MARVIN GANGBIN uvvewro HUEB/VER 8 WORREL .477URNEK9 United States Patent 3,152,763 THECHAL DAYLIGHT FKXTURE Marvin Gangbin, 903 lilolrer St, Marlera, Qalif. Filed .l'une 9, I960, Ser. No. 34,960 3 Claims. (Cl. Will-11) The present invention relates to an artificial daylight fixture and more particularly to a lighting fixture adapted to emit light which closely simulates natural daylight.

It is well-known that the energy in the suns radiation reaching the earth is substantially uniformly distributed throughout the visible spectrum. Therefore, natural daylight contains substantially uniform amounts of the colors or wave lengths of light in the visible spectrum. When objects are viewed in natural daylight, therefore, they appear in what may be regarded as their true colors.

Under conventional artificial light, true color is seldom observable. That is, many lighting fixtures produce light which peaks in a relatively narrow band and does not encompass a sufliciently wide band of frequencies in the visible spectrum. As a result, color distortion usually occurs.

Especially there has been a lack of lighting fixtures in the home lighting field which have a high quality light output. Normally, domestic fixtures consist of single incandescent or fluorescent lamp units which do not produce the broad band of wave lengths desired. Accordingly, walls, drapes, carpets, and the like, do not appear light.

Another object is to provide a lighting fixture of the nature described which is adapted for home use.

Another object is to mount a plurality of fluorescent lamps of predetermined characteristics in a reflective housing in a predetermined relation to each other and to the housing.

Another object is to provide a lighting fixture in which the color of the lamps employed, their spaced relationship in the fixture, and their dimensional relationship to the housing in which they are mounted, as well as other features of the fixture, are critically balanced and related so as to produce a total light output containing a broad range of Wave lengths in the visible spectrum.

Another object is to provide a lighting fixture of a plurality of fluorescent lamps selected and mounted in a housing of predetermined size, shape and reflective ability so as to produce a blended composite light output having a spectral curve similar to that of natural daylight.

Other objects are to provide a lighting fixture which is simple and economical to construct, dependable in op eration, durable, and, although particularly adapted for domestic use, has a wide variety of other applications.

These, together with other objects, will become more fully apparent upon reference to the following description and accompanying drawing.

In the drawing:

FIG. 1 is a side elevation of a lighting fixture embodying the principles of the present invention.

FIG. 2 is a somewhat enlarged top plan view of the lighting fixture of FIG. 1.

FIG. 3 is a fragmentary transverse section taken on line 3-3 of FIG. 2.

Referring more particularly to the drawing, an indirect lighting fixture illustratively embodying the principles ice of the present invention includes an upright base 10 of any desired configuration and design. The base has a lower end 11 adapted to rest on the floor or other support and an upper end 12. A threaded mounting post 13 is connected to the upper end of the base and is extended axially upwardly therefrom.

The subject fixture further includes a substantially circular, preferably metallic, housing 16 having a circular bottom wall 17 concentrically receiving the post 13. A nut 18 is screw-threaded on the post and turned down tightly against the bottom wall. The housing also includes a lower bowl portion 20 concentrically secured, as by Welding, to the bottom wall and providing a lower apex portion 21 rested on the upper end 12 of the base 10 about the post. In this manner the bottom wall is mounted in a horizontal position when the base is erect. A panel 22 is fitted within the bowl portion in downwardly spaced relation to the bottom wall for a purpose to be described.

The housing 16 also provides an annular side wall 25 :connected in circumscribing relation to the bottom wall 17 and upwardly extended therefrom. Preferably the side wall is slightly upwardly divergent and thereby has an outer concave surface 2 6. The side wall terminates in an upper circular edge 27 circumscribing an open top for the housing. Both the bottom wall 17 and the side each other, as will be evident by reference to FIG. 2. A

plurality of elongated cylindrical, substantially parallel, transversely spaced, electrically energizable fluorescent lamps 37 through 42 are individually received in the pairs of tube holders 36. Specifically, these lamps have opposite ends 44 and 45 providing outwardly extended prongs 46 received in sockets in the tube holders in a manner well understood.

The intermediate fluorescent lamps 38, 39, 40 and 41 are substantially rectangularly arranged in that their opposite ends 44 and 45 terminate in upstanding parallel planes normal to the bottom wall and to a plane of symmetry for the housing 16 extended diametrically of the bottom wall 17 between the innermost lamps 39 and 40. While all of the lamps have longitudinal axes disposed in a substantially common plane parallel tothe bottom wall, the outermost lamps 37 and 42 have their opposite ends terminating inwardly relative to the opposite ends of the intermediate lamps. However, the opposite ends of the lamps 37 and 42 are also located in parallel planes normal to the'bottom wall and to said plane of symmetry.

The location of the lamps 37 through 42 in thehousing 16, the characteristics of the lamps, and the dimensional relationship between ,the lamps and the housing are found to be critical inorder to yield the optimum results obtainable. Thus, the, innermost lamps 39 and 40 are cool white and are located in substantially equally spaced relation on opposite sides of said plane of symmetry. The watts generated for each of these lamps separately within the various color bands of the spectrum are as follows: 2.46 watts in the violet to blue range; 3.48 watts in the green to yellow range; and 2.11 watts in the orange to red range. Further, each cool white lamp has a spectral curve which has a major peak at approximately 5800 angstrom units and a sub-peak at approximately 4900 angstrom units. The cool white lamps, in a preferred embodiment of the invention, each have an outside diamof a slightly larger diameter.

a eter of approximately 1 inch and a light emitting length of approximately 16% inches. In addition, in such preferred embodiment, these lamps are spaced approximately 2% inches apart, center to center.

The lamps 38 and 41 are of the same diameter and length as the cool white lamps 39 and 40' in the described preferred embodiment but are red lamps. These red lamps emit no visible radiation in the violet to blue range of the spectrum, emit 0.02 watts in the green to yellow range; and 1.69 watts in the orange to red range. Each of these lamps has a spectral curve peaking at approximately 6500 angstrom units. These lamps are substantially equally spaced from their adjacent cool white lamps and in said preferred embodiment this space is approximately 2% inches.

The outermost lamps 37 and 42 are blue and, in the preferred embodiment, are outwardly laterally spaced from their respectively adjacent red lamps by approximately 3% inches. Each blue lamp produces 4.91 watts in the violet toblue spectral region and 1.67 and 0.20 Watts in the green to yellow and orange to red regions, respectively. The spectral curve of the blue lamps indicates that they each peak at approximately 4400 angstrom units. It is noted that the blue lamps are shorter than the intermediate lamps 38, 39, 40 and 41 but are In the preferred embodiment, the blue lamps have an outside diameter of approximately l /2 inches and a light emitting length of approximately 13% inches.

Further considering the critical relationship of the lamps 37 through 42 and the housing 16, it is to be noted that the common plane of the lamps is located closer to the bot-tom wall 17 of the housing than to the upper edge 27 thereof. In the preferred embodiment continuously referred to herein, this plane is approximately 1% inches from the bottom wall while the distance from the bottom wall to the upper edge is approximately 2% inches. Further, in this preferred unit, the housing has an average diameter measured midway of the upper edge and the bottom wall of approximately 22 /2 inches.

A plurality of fluorescent lamp starters 50 are mounted in sockets 51 therefor on the panel 22 and extend upwardly through openings in the bottom wall 17. Although not illustrated, suitable electrical wiring is provided in the fixture and connected to the tube holders 36 and sockets 51 so that with the lamps 37 through 42 in their respective tube holders and voltage applied, the lamps will be energized. Furthermore, it is desirable to enable control of only certain combinations of the lamps under certain circumstances. However, in order to provide a lamp output which closely simulates natural daylight, it is necessary that all of the lamps be energized simultaneously.

Operation The operation of the described embodiment of the subject invention is believed to be readily apparent and is briefly summarized at this point.

Thelamp .fixture described is particularly adapted for domestic use and is preferably located on the floor or other support so that the open top of the housing 16 is directed upwardly. Voltage is then applied to the lamps 37 through 42 by manipulation of a switch, not shown, on the fixture. All of the lamps are simultaneously illuminated.

The composite light output of the fixture is, of course, a result of the direct light emitted directly upwardly from each of the lamps 37 through 42 and the light reflected from the coating 32 on the side and the bottom walls 25 and 17. The direct and reflected light intermix to yield a combined output distinguishable from the individual lamp outputs. It has been found that by employing the precise lamps described in the precise relationship noted above that this composite light output very closely simulates the suns radiation as it reaches the earth. That is,

the spectral curve of the subject fixture is similar to the known spectrum curve of the suns radiation and embraces a relatively wide range of wave lengths in the visible spectrum.

It has been found in use of the subject fixture that ceilings, carpets, drapes, and the like, appear substantially in their true color. Regardless of the color of such items viewed under the light of this fixture, there is a minimum of color distortion.

Although the invention has been herein shown and described in whatis conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of the invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices and apparatus.

Having described by invention, what I claim as new and desire to secure by Letters Patent is:

1. An indirect lighting fixture adapted to simulate actual daylight comprising a substantially circular housing including a flat bottom Wall and an annular side wall upwardly extended from the bottom wall, the bottom and side wall having inside surfaces; a coating of highly reflective material on the inside surfaces of the bottom and side walls of the housing; a pair of elongated electrically energizable white fluorescent lamps mounted on the bottom wall of the housing in a substantially common plane parallel to the bottom wall and substantially equally spaced on opposite sides of a predetermined plane extended diametrically of the housing; a pair of elongated electrically energizable red fluorescent lamps mounted on the bottom wall of the housing in substantially the same plane as the white lamps and substantially equally outwardly spaced from the white lamps on opposite sides of said plane of symmetry; and a pair of elongated electrically energizable blue fluorescent lamps mounted on the bottom wall of the housing and substantially the same common plane as the white and red lamps and substantially equally outwardly spaced from the red lamps on opposite sides of said plane of symmetry, said white, red and blue lamps being in substantially parallel relation wherein the white and red lamps are of substantially the same length and diameter and have opposite ends terminating in substantially parallel planes normal to the bottom wall and to said plane of symmetry, and wherein the blue lamps are of substantially the same diameter and length and have opposite ends terminating in spaced parallel planes normal to the bottom wall and said plane of symmetry, the diameter of the blue lamps being greater than the diameter of the white and red lamps, and the planes in which the ends of the white and red lamps terminate being located outwardly of the blue lamps from the planes in which the ends of the blue lamps terminate.

2. An indirect lighting fixture adapted to simulate actual daylight comprising a substantially circular housing including a flat bottom wall and an annular side wall upwardly extended from the bottom wall, the bottom and side wall having inside surfaces; a coating of highly reflective material on the inside surfaces of the bottom and side Walls of the housing; a pair of elongated electrically energizable white fluorescent lamps mounted on the bottom wall of the housing in a substantially common plane parallel to the bottom Wall and substantially equally spaced on opposite sides of a predetermined plane extended diametrically of the housing; a pair of elongated electrically energizable red fluorescent lamps mounted on the bottom wall of the housing in substantially the same plane as the white lamps and substantially equally outwardly spaced from the white lamps on opposite sides of said plane of symmetry; and a pair of elongated electrically energizable blue fluorescent lamps mounted on the bottom wall of the housing and substantially the same common plane as the white and red vAAAHA 5 lamps and substantially equally outwardly spaced from the red lamps on opposite sides of said plane of symmetry, said white, red and blue lamps being in substantially parallel relation wherein the side wall of the housing has an upper annular edge spaced from the bottom wall of the housing a distance substantially equal to the spacing between the adjacent white and red lamps, and wherein the common plane of the lamps is located closer to the bottom wall than to said upper edge.

3. An indirect lighting fixture adapted to emit light closely simulating natural daylight comprising an upright stand, a substantially circular housing mounted on the stand including a substantially horizontal flat bottom wall and an annular side wall integrally upwardly extended from the bottom wall and terminating in an annular upper edge circumscribing an open top for the housing, the bottom and side walls having inside surfaces; a reflective white enamel coating on the inside surfaces of the side and bottom walls; a pair of elongated cool white fluorescent lamps having opposite ends and of substantially the same diameter and length mounted on the bottom wall in a substantially common plane parallel to the bottom wall and in substantially equally spaced parallel relation on opposite sides of a vertical plane of symmetry diametrically related to the bottom wall of the housing, the opposite ends of the lamps being in closely adjacent spaced relation to the side wall of the housing; a pair of elongated electrically energizable red fluorescent lamps of the same diameter and length as the white lamps and mounted on the bottom wall in substantially the same plane as the white lamps and substantially equally individually transversely outwardly spaced from the white lamps, the white and red lamps being in substantially rectangular relationship with adjacent ends thereof terminating in common vertical planes normal to said plane of symmetry; and a pair of elongated electrically energized blue fluorescent lamps having opposite ends and being mounted on the bottom wall in substantially the same plane as the white and red lamps and substantially equally individually transversely outwardly spaced from the red lamps between such red lamps and the side wall of the housing, each of the blue lamps having a diameter approximately one and one half times the diameter of the white or red lamps and a length shorter than the length of the white and red lamps, the opposite ends of the blue lamps being in closely adjacent inwardly spaced relation to the side wall of this housing, the distance between adjacent White and red lamps being approximately two and three fourth times the diameter of each white and red lamps, the blue lamps being spaced from their adjacent red lamps by an amount approximately equal to three and one fourth times the diameter of a white lamp, the diameter of the housing being approximately twenty-two and one half times greater than the diameter of a white lamp, the distance between the bottom wall and the upper edge of the housing being substantially equal to the spacing between adjacent white and red lamps, and the distance between the common plane of the lamps and the bottom wall being less than half of the distance between the bottom wall and said upper edge.

References Cited in the file of this patent UNITED STATES PATENTS 2,003,342 Cavanaugh June 4, 1935 2,125,319 Schlumbohm Aug. 2, 1938 2,451,580 Schwinger Oct. 19, 1948 2,725,461 Armour Nov. 29, 1955 FOREIGN PATENTS 844,563 France Apr. 24, 1939 1,065,989 France Jan. 13, 1954 

1. AN INDIRECT LIGHTING FIXTURE ADAPTED TO SIMULATE ACTUAL DAYLIGHT COMPRISING A SUBSTANTIALLY CIRCULAR HOUSING INCLUDING A FLAT BOTTOM WALL AND AN ANNULAR SIDE WALL UPWARDLY EXTENDED FROM THE BOTTOM WALL, THE BOTTOM AND SIDE WALL HAVING INSIDE SURFACES; A COATING OF HIGHLY REFLECTIVE MATERIAL ON THE INSIDE SURFACES OF THE BOTTOM AND SIDE WALLS OF THE HOUSING; A PAIR OF ELONGATED ELECTRICALLY ENERGIZABLE WHITE FLUORESCENT LAMPS MOUNTED ON THE BOTTOM WALL OF THE HOUSING IN A SUBSTANTIALLY COMMON PLANE PARALLEL TO THE BOTTOM WALL AND SUBSTANTIALLY EQUALLY SPACED ON OPPOSITE SIDES OF A PREDETERMINED PLANE EXTENDED DIAMETRICALLY OF THE HOUSING; A PAIR OF ELONGATED ELECTRICALLY ENERGIZABLE RED FLORESCENT LAMPS MOUNTED ON THE BOTTOM WALL OF THE HOUSING IN SUBSTANEQUALLY OUTWARDLY SPACED FROM THE WHITE LAMPS ON OPPOSITE SIDES OF SAID PLANE OF SYMMETRY; AND A PAIR OF ELONGATED ELECTRICALLY ENERGIZABLE BLUE FLUORESCENT LAMPS MOUNTED ON THE BOTTOM WALL OF THE HOUSING AND SUBSTANTIALLY THE SAME COMMON PLANE AS THE WHITE AND RED LAMPS AND SUBSTANTIALLY EQUALLY OUTWARDLY SPACED FROM THE RED LAMPS ON OPPOSITE SIDES OF SAID PLANE OF SYMMETRY, SAID WHITE, RED AND BLUE LAMPS BEING IN SUBSTANTIALLY PARALLEL RELATION WHEREIN THE WHITE AND RED LAMPS ARE OF SUBSTANTIALLY THE SAME LENGTH AND DIAMETER AND HAVE OPPOSITE ENDS TERMINATING IN SUBSTANTIALLY PARALLEL PLANES NORMAL TO THE BOTTOM WALL AND TO SAID PLANE OF SYMMETRY, AND WHEREIN THE BLUE LAMPS ARE OF SUBSTANTIALLY THE SAME DIAMETER AND LENGTH AND HAVE OPPOSITE ENDS TERMINATING IN SPACED PARALLEL PLANES NORMAL TO THE BOTTOM WALL AND SAID PLANE OF SYMMETRY, THE DIAMETER OF THE BLUE LAMPS BEING GREATER THAN THE DIAMETER OF THE WHITE AND RED LAMPS, AND THE PLANES IN WHICH THE ENDS OF THE WHITE AND RED LAMPS TERMINATE BEING LOCATED OUTWARDLY OF THE BLUE LAMPS FROM THE PLANES IN WHICH THE ENDS OF THE BLUE LAMPS TERMINATE. 